Power unit



`o. A. FRITZ June 7, 1938.

POWER UNIT 3 Sheets-Sheet 1 Filed sept. 25, 193e nl W,

June 7, 1938. o. A. FRITZ POWER UNIT Filed sept. 23, 1936 5 Sheets-Sheet2 O. A. FRlTZ June 7, 1.938'

POWER UNIT Filed Sept. 23, 1936 `3 Sheets-Sheet 3 s/ Illllllllllllllllllllllllil.lwlllllllll Patented June 7, 1938 UNITEDSTATES PATENT OFFICE 7 Claims.

This invention relates to a power unit designed primarily for use inconnection with window shade rollers, but it is to be understood that apower unit, in accordance with this invention, is to be employed fordriving any object for which it may be found applicable. The inventionaims to'provide, in a manner as hereinafter set forth, a power unit forattaching to a tubular member, to form in connection with the latter, awindow shade or winding roller drivennfrom the unit; for obtaining asmoother action of a winding roller with respect to the action of windowshade or winding rollers now generally used;Y for preventing a windowshade from flying back when released to wind on its roller; capable ofbeing attached to a tubular member of any suitable length to form awinding roller of the desired length for window shades of differentwidths; for overcoming the necessity of employing pivot pins for thelatching dogs or pawls employed in units of the class to which thisinvention belongs; and for positioning the latching dogs orY pawlswithin and flush with the side faces of the body of'a carrier, as wellas forming the dogs and carrier with coacting inherent parts to providefor the freely fulcruming of the dogs to and from roller latchingposition.

The invention further aims to provide, in a manner as hereinafter setforth, a power unit designed primarily for window shade rollers andwhich is simple in its construction and arrangement,V strong, durable,compact, thoroughly efficient in its use, forming a part of and adaptedto be connected to the remaining part of a winding roller, readilyassembled, and comparatively inexpensive to manufacture.

With the foregoing and other objects in view the invention consists ofthe novel construction,

combination and arrangement of parts as will be more specificallydescribed and are as illustrated in the accompanying drawings wherein isshown embodiments of the invention, but it to be understood thatchanges, variations and modications may be resorted to which fall withinthe scope ofthe invention as claimed.

In the drawings:

Figure 1 is an elevation of a shade roller having the power unitinstalled therewith,

Figure 2 isa longitudinal sectional View of the power unit wheninstalled relatively to the shade roller,

Figure 3 is an exploded view in elevation and perspective of theelements of the power unit other than the housing or casing for saidrunt,

Figure 4 is an elevation of a blank from which (Cl. 156-36)V is formedthe coupling element for one end of the outer power transmitting`spring,

Figure 5 is' a longitudinal sectional View of a modified form of powerunit in accordance with this invention showing the same installed withre- 5 spect to the roller, t

Figure 6 is an elevationof the elements of the power unit of themodified form shown in Figure 5 with the omission of the housing orcasing for the elements, y ,10

Figure is an elevation of aA vshade roller including a power unit inaccordance with this invention land'provided with means for attachingthe shade tothe periphery thereof, and Figure 8 is a f'ra'gr'nentaryview in perspective 515 illustrating windowrsha'de and themeans on theroller for attaching the shade to the latter.

' `Figure"9 is a longitudinal sectionalview of still another modifiedform, and

FigurelO is a disassembled view of the elements .H520 of the'modified-form shown in Figure 9 with the exception of the outer powertransmitting spring.

Referring to YFigure y1 of the drawings a winding rollerv is illustratedand formed from a pair of tubular inter-engaging sections I, 2. Thesection 25 I is of materially l'essllength than section 2 andconstitutesthe casing or'housing of a power unit in accordancew'ith-thisinvention. 'I'he section 2 at its outer end `is providedvwith arotatable pint-le 3 for mounting lin a bracket not shown. Af30 Thesections I, `2'fri ct`ii nally revolve together and section I has'areduced inner end' terminal portion 4 forming afperlpheial shoulder`5.The end terminal portion extends Ainto the inner end of the section 2.The innerend edge of the latter "35 abut-s the shoulder 5." 'The portion4 frictionally engages witlifthe 'inner face of section 2. The section-I is capableof being detachably connected to a section'2 vof anydesired length and whereby vsuch'arrangement permits window shades ofdif- 140 ferent widths to be attached tothe roller.

With reference tol Figures 2 and`3, they illustrate a power-unit inaccordance with this invention and as aforestated, the section I formsthe casing vor housingrfor the yelements of the ":45 said power unit.The reduced endterminal portion vil of the section I is of materiallyless length than the'remainingportio'n S of such section. The reducedterminal portion 4 is inset with respect to the portion 6 of section Ithereby prove150 viding'. the section 5 at its inner end with aninternal shoulder l. vThe unit includes a stationary shaft 8 havingattached with its outer end a's'quare pintle I9 for mounting in asuitable bracket not shown.' The-inner end terminal por- 55 tion I8 ofshaft 8 is formed with a diametrically extending groove I2 and adiametrically extending opening I3 disposed at right angles to andintersected by the groove I2. The opening I3 is arranged in proximity tothe base wall I5 of the groove I2. The shaft 8 has mounted on its outerend a cylindrical socket forming member I6 consisting of a body part |11having integral with its outer end I8 the pintle 9. The shaft 8 extendsinto the inner end of the member I6 and the latter is anchored to shaft8 by the pin I9 passing through registering openings (Figure 2) disposeddiametrically of the body part I1 of member I5 and the shaft 8. Theopenings in said body part I1 are indicated at I9ab and the opening inshaft 8 at I9b. The pin I8 has its ends extend from the outer ends ofthe openings I9b for a purpose to be referred to. The body I1 is ofcircular cross section and is provided between its transverse median andouter end with an outwardly directed annular flange 28. The body I1outwardly adjacent the flange 28 is formed in its periphery with a pairof diametrically pposed depressions 2|, 22. The depressions 2|, 22 arepositioned in proximity to the end I8. It is to be understood that theshaft 8 and member I6 may be set up from a single length of suitablematerial. That portion of the outer periphery of the body I1 arrangedoutwardly with respect to the flange 20 constitutes a bearing surface23.

Mounted on the surface 23 is a carrier 24 in the form of an annulus ofgreater diameter than the flange 2|). The carrier 24 is revolublymounted on the surface 23 and bears against the flange 28. The body ofthe carrier 24 is of a desired thickness and is indicated at 25. Theinner and outer edges of body 25 are designated 26, 21 respectively. Thebody 25 is formed with a. pair of diametrically opposed and oppositelydisposed cutouts 28, 29 of like form and which open at the inner edge 26of body 25. Each of said cutouts consists of a circular portion 38, asegmental wall 3| arranged eccentrically to the edge 21, an inclinedwall 32, and an inclined wall 33. The circular portion 38 is arranged atone end of the wall 32 and the latter merges into the inner end of saidcircular portion and into the edge 26. The walls 32, 33 are oppositelyoutwardly inclined. The wall 33 merges at one end into the edge 26 andat its other endl into one end of the wall 3|. The wall 3| at its otherend merges into the outer end of a circular portion 30. The circularportions 38 of the said cutouts constitute fulcrums.

Mounted in the cutouts 28, 29 are a pair of oppositely disposed latchingdogs or pawls of like contour and which operate through the openings 34provided by the cutouts. The dogs are of less thickness than that of thebody of the carrer 24. Each dog consists of a circular end portion 35, ashank 36 which is integral at one end with the end portion 35 and isformed adjacent its other end with a substantially triangular-shapednose 31a. That end of the shank of the dog which is integral with theend portion 35 of the dog is eccentrically disposed with respect to suchportion 35. The end portions 35 of the dogs are mounted in the circularportions 30 of the cutouts and the said portions 35 are capable ofshifting in the portions 30. The side faces of the dogs are flush withthe side faces of the body 25 of the carrier 24. On the revolving of thecarrier 24 the noses of the dogs ride on the bearing surface 23. Thenoses of the dogs are capable of engaging with the depressions 2| and 22for latching the carrier 24 from movement. The noses of the dogs arediametrically disposed with respect to the carrier 24.

Encompassing the carrier 24 and bodily moving therewith is an annularcoupling member 31 formed of an outer end part 38, an inwardly extendingintermediate part 39, a rearwardly extending partY 46 and inwardlyextending inner parts 4I. Formed integral with the part 40 atdiametrically opposite points of the latter and between the ends of theparts 4| is a pair of rearwardly extending parallel arms 42, 43 of likeform and each has its end terminal portion formed with a plurality ofslits. The portions of the material freed by the slits in the arm 42 or43 are oppositely disposed as indicated at 44, 45 to provide a couplerof split loop-like form at the rear end of the arm. The part 38 ispositioned against the edge 21 of the carrier 24; the part 39 ispositioned against the inner face of the carrier 24; the part 4I! ispositioned against the edge of the flange 28; the part 4I is positionedagainst the rear face of the flange 20 and seats on the body I1.

Mounted within the section I at the outer end thereof, suitablyconnected therewith for the purpose of revolving therewith, bearingagainst the outer face of carrier 24, seated on the part 38 of member 31and engaging the rear face of the part 39 of member 31 is a combinedcoupling and cap member 46. The member 46 has an axial opening 41 forthe passage of the pintle 9 and an inturned flange 41a at itsinner end.The member 46 couples carrier 24 and member 31 together. The member 46,carrier 24 and member 31 bodily revolve together with the section Iwhich constitutes the housing or casing of the elements of the unit.

The unit shown in Figures l to 4 includes an inner and an outer powertransmitting spring indicated at 48, 49 respectively. 'I'he springs arewound in a like direction to increase the tension thereof and expand ina like direction when winding the roller.

The spring 48 encompasses shaft 8. Mounted on the rear portion of thebody I1 of member I6 and extending rearwardly from the latter is asleeve 50 which surrounds the spring 48. The sleeve at its outer endabuts the parts 4| of the member 31 and at its rear end abuts a washermounted on shaft 8. The sleeve 56 in proximity to its forward end isformed with a pair of diametrically opposed openings 5l)a which registerwith the openings I9a and receive the extended ends of the pin I9(Figure 2) whereby the shaft 8, member I6 and sleeve 58 are coupledtogether. Extending through `the opening I3 of shaft 8 is a pin 52 whichprevents the rearward movement of the washer 5|. The rear end of thespring 48 is extended through the groove I2 whereby shaft 8 and saidsprings are connected together. The sleeve 5I] at its forward end isslitted for a length greater than that portion of body I1 on whichsleeve 50 is mounted. 'Ihe material freed by the slits in the forwardend of sleeve 50 provides a resilient tongue 54 formed adjacent memberI6 with a transverse inset part 55 through which passes the forward endterminal portion of the spring 48 whereby the tongue in connection withthe inner face of sleeve 58 provides for connecting spring 48 and sleeve58 together. Spring 49 encompasses sleeve 5D and has its rear endextending through a slit 56 and an opening 51 formed in the sleeve 50whereby the latter and spring 49 are connected together. The forward endof the spring 49 is passed through the couplers "formed on the free endsof the arms 42 Awhereby spring 48 and member 31 are connected together.

The mounting of the springs 48, 49 in a manner as stated provides forthe winding together in one direction and the unwinding or expansionthereof in the opposite direction.

With reference to Figure 4, it discloses a blank indicated at 58 fromwhich member 31 is formed. The blank 58 is of cap-like form providedwith a pair of oppositely disposed, segmental-shaped cutouts 59, a pairof slits 60, a pair of slits 6|, a slit 63 and another pair of slits 64.The material freed by the slits 60, 6|, 62 and cutouts 59 is bentoutwardly to provide the arms 42 of the member 31. The material freed bythe slits 63, 64 is bent in a manner as indicated at 44, 45 (Figure 2)`to provide the couplers for the outer end of spring 49. The pair ofslits 60, the pair of slits 6| and the cutouts 5S coact to provide as apart of the blank a pair of oppositely disposed segmental portions 64a,64b arranged in endwise spaced relation and which constitute the parts4| of member 31.

With reference to Figures 5 and 6, they illustrate a modified form of apower unit in which a single power transmitting spring is employed. Thepower unit shown in Figures 5 and 6 is generally indicated at 64 and itdoes not include a spring 49, the sleeve 50, the washer 5| and pin 52.The stationary shaft of the unit 64 is indicated at and is of the sameform as the shaft 8 with this exception, that shaft 65 is not providedwith an opening |3. The power transmitting spring of the unit 64 isindicated at 69 which has its rear end extending through groove 69a inshaft 65 whereby the latter and spring 69 areconnected together. Theforward end of the spring 69 is coupled to the arms 42 of the member 31.Otherwise than that as stated, the form shown in Figures 5 and 6 will bethe same as that shown in Figures l to 4.

With reference to Figures '1 and 8, the sections of the shade or windingroller are indicated at 10, 1|. Section 19 corresponds to section. ofthe power unit. Section 1| corresponds to section 2 referred to. Section10 is provided with a pair of spaced Yfastener members 12 for attachin gthe shade 13 thereto. The section 1| is provided with two spaced pairsof fastener members 14 for attaching shade 13 thereto. The fastenermembersv are of like construction and are provided from inherent partsof the sections 10. 1|. The said sections 10, 1| are slitted and thematerial freed by each slit forms a fastener member. Each fastenermember comprises a body part 15 formed with a bendable barb 16. Shade 13is inserted under the body 15 of the fastener members vand the barbs 16are bent iny a manner to extend through the shade 13. The fastenermembers are then pressed inwardly not only to bind butto connect theshade 13 with the shade or winding roller.

With reference to Figure 3, there is shown interengaging means toprovide for the bodily revolving of the carrier 24, coupler member 31and cap member 46.' The said means consists of a pair of edge grooves 11in the carrier 24, a pair of inset portions 18 on member 31 which engagein the grooves 11 and a pair of inset portions 19 on member 46 whichengage Vin grooves formed in member 31.

With reference to Figures 9 and l0, they ininclude a pair of tubularinterengaging sections 80, 8| of the same construction and arrangementas the tubular sections 2.

The power transmitting unit shown in Figures 9 and 10 includes astationary shaft `82 formed with a reduced outer end terminal portion83, a socket 84 in the latter, an opening 85 intersecting the socket, ashoulder 86 at the inner end of portion 83, a groove 81 lengthwisethereof at its inner end and an opening 88 intersecting the groove.Encompassing the shaft 82 is an inner power transmitting spring 89having the inner end terminal portion 90 thereof bent to extend throughthe groove 81 whereby one end of spring 89 is anchored to shaft 82.Positioned on the latter in proximity to its inner end is a washer 9|which is retained on the shaft 82 by a pin 92 extending through opening88.

The power transmitting unit shown in Figures 9 and 10 includes arevoluble coupling member 98, stationary washers 94, preferably offibrous material, a stationary head member 96, a stationary pintleforming member 91, a revoluble carrier 98, a pair of oppositely disposedpawls or dogs 99, |00, a revoluble cap member |0|, a securingpin |00, asleeve |02 and an outer power transmitting spring |03 which encompassesthe sleeve |02. The latter surrounds the spring 89.

1e coupling member 93 consists of an annulus HiT-3a formed atdiametrically opposed pointsl of its outer edge with a pair ofrearwardly extending oppositely disposedV arms |84, |05 provided attheir rear ends with outwardly directed anges |06, |01 respectively. Theannulus |033a is also provided at diametrical points on its outer edgewith forwardly directed segmental shaped oppositely disposed flanges|08, |09, each arranged between the arms |04, |05 respectively. Eachforwardly directed flange extends from one sideedge of the arm |04 toone side edge of the arm |05.

faces.

The head member 96 comprises a tubular body part |I| formed with aclosure I2 at'its outer end provided with an axial opening AH3. Theinner portion of the body part has pairs lof lengthwise slits ||4terminating at one end at the inner edge ||5 thereof. The material freedby the slits |54 is bent outwardly substantially at right angles to thenon-slitted portion of body part and provides a series of spacedradially disposed .wings I6. The non-slitted portion of body partoutwardly adjacent the wings H6 is formed with a pair of diametricallyopposed openings |1, A| I8.

The pintle forming member 91 comprises a rectangular head 9 havingextending rearwardly therefrom a tapered shank |20 formed with anopening 12|. The shank |20 at its forward end is integral with the rearend-of head H9. The forward end of shank |20 is arranged inwardly of theside faces of head I9 thereby providing a shoulder |22.

I'he carrier 98 is in the form of an annulus r|23 of the desiredthickness and constructed in the same manner as the carrier 2t. Thepawls or dogs 99, |00 are constructed in the same manner as the pawls36, 31. The p-awls 99, |00 are arranged in the annulus |23 in the samemanner as the pawls 86, 31 are arranged in the carrier 24 and for thesame purpose as pawls 36, 31. The outer edge of annulus |23 isA formedwith a pair of Adiametrically opposed grooves |24.

The cap member |0|` is arranged relative Vto 'Ihe flanges |08, |09 aretrans- -versely grooved, as at H9 in their outer side section 8i! in thesame manner as cap member @f5 46 is arranged relative to section l. Thecap member |0| is similar in construction to that of cap member 46. Theinwardly opposed extending diametrically opposed protuberances or insetparts on the rim of the flange of cap member |91 are indicated at |24aand they function for the same purpose as the parts 19 of cap member 46.The cap member |0| is suitably secured to and within section 80.

The sleeve |02 adjacent its forward end has an opening |25 into whichextends the outer terminal portion |26 of spring 89. By the arrangementaforesaid of the spring 89 relative to shaft 82 and sleeve |02, the rearterminal portion 90 of spring 89 is anchored to shaft 82 and its forwardterminal portion |26 to sleeve |02. The rear end of the latter isslitted diametrically at opposite points, as at |21, |28 and thematerial freed by the slits outset to form a pair of latching arms |39,|3| for the rear end terminal portion |32 of the spring |03. The forwardend terminal portion |32 of the spring |03 extends around the arms |94,|05 and is extended into an opening |33 in arm |94 whereby the couplingmember 93 and spring |03 are connected together.

When the unit shown in Figures 9 and 10 is set up, the coupling member93 is arranged on the head member 96 rearwardly of the wings ||6.Interposed between member 93 and the wings H6 is the washer 94. Theforward end portion of sleeve |02 is mounted upon the rear portion ofhead member 96 and abuts the annulus |03a of member 93. The washer `95is -arranged on member 96 forwardly of wings H6. The reduced part 83 ofshaft 82 extends into member 96. The shoulders 86 abut the inner ends ofa pair of wings ||6. 'I'he carrier 98 with the pawls 99, |00 arrangedtherein is mounted on member 96 outwardly relative to washer 95. Themember 93 is arranged on member 96 outwardly relative to` carrier 98 andencompasses carrier 98 and ilanges |08, |09 of member 93, as well asoverlapping the outer edge of the body part of member 93. The shank |29of member 91 is extended through members 96, |0| into the socket 84 ofshaft 22. The shoulder |22 of member 91 abuts the end ||2 of member 96.The shank |20 is anchored to shaft 82 by pin |00au mounted in openings85, |2|. When the unit is assembled the parts |24a of cap member |0| areseated both in the grooves H6 of member 93 and the grooves |24 ofcarrier 98 whereby member 93, carrier 98 and member |0| will bodilyrevolve in unison about member 96. It is to be understood that othersuitable means may be employed for bodily revolving the members 83, |0|and carrier 98. The pawls or dogs 99, |09 coact with the openings ||1,||8 in member 96 fory latching the unit when occasion requires.

What I claim is:

1. In a power unit for the purpose set forth, a stationary shaft elementincluding a squared pintle at one end, an annular ange in proximity tothe inner end of the pintle and a circular part between the pintleandthe flange, said part being of less diameter than that of the flange andhaving its periphery formed with diametrically disposed depressions, astructure surrounding said shaft and revoluble in opposite directionsrelative to said shaft and including a carrier in the form of an annulusencompassing said part of said element and a pair of oppositely disposeddogs for engaging in said depressions for latching said structure frommovement, said dogs being housed by said carrier, said carrier and dogshaving inherent coacting parts to provide for the fulcruming of the dogsin and on the carrier, and a spring means connected with said shaft andstructure to provide for the revolving of the latter in one directionwhen the dogs are free of latching position, said dogs when innonlatching position and during the revolving of said structure ridingon the periphery of said part of said element between said depressions.

2. In a power unit for the purpose set forth, a revoluble cylinderadapted to form one of the sections of the body of a shade roller, astationary shaft'elernent mounted in said cylinder, a structurerevoluble about the outer end of said element connected to and bodilymoving with said cylinder, an inner power transmitting springencompassing said element and connected to the inner end of the latter,a sleeve encompassing said spring, said sleeve having means forconnecting the outer end of said sleeve thereto, an outer pow-ertransmitting spring encompassing said sleeve, said sleeve having itsinner end provided with means for connecting one end of said outerspring, said structure including means for connecting the outer end ofsaid outer spring thereto, and said structure including oppositelydisposed dogs fulcruming therein and engagable in said element forlatching said structure from movement.

3. In a power unit a revoluble cylinder, a stationary shaft arrangedwithin said cylinder, an inner power transmitting spring encompassingand having its inner end connected to said shaft, a socket formingmember mounted on and secured to the outer end of said shaft, saidmember provided intermediate its ends with an annular flange and withperipheral spaced depressions in proximity to and outwardly of saidflange, an annulus revoluble about said depressions and formed with apair of oppositely disposed cutouts opening at the inner edge of theannulus, oppositely disposed latching dogs arranged in said cutouts forengaging in said depressions for latching the cylinder from movement,said cutouts having edge portions, said dogs having means fulcruming onsaid edge portions, means arranged within and xed to said cylinder,encompassing said annulus and ange and formed with inwardly extendingarms provided on their free ends with couplers, a sleeve mounted on saidspring and provided with means for connecting the outer end of saidspring thereto, and an outer spring encompassing said sleeve and havingits inner end extending through the body of the sleeve for connectingthe latter and outer spring together, said outer spring having its outerend extending through said couplers.

4. In a power unit a revoluble cylinder, astationary shaft elementmounted therein and extending outwardly therefrom, an annulus revolubleon said element and being formed with a pair of oppositely disposedcutouts opening at the inner edge of the annulus, a coupling memberfixed to and surrounding the annulus, revoluble about said element andformed with inwardly extending arms provided with couplers, oppositelydisposed dogs arranged within said cutouts, fulcruming on the edgeportion of the cutouts and engageable in said element for latching thecylinder from movement, a power transmitting spring within said cylinderand having its outer end anchored to said couplers and its inner endanchored to the inner portion of the shaft element, a cap within andfixed to one end of said cylinder for revolving the latter, said capbeing revoluble on the shaft element, said member having a partencompassing said annulus, said cap encompassing said part, and saidcap, part and annulus having coacting interengaging means for connectingthem together for bodily revolving in unison.

5. In a power unit a revoluble cylinder, a stationary shaft elementarranged within the cylinder, an inner power transmitting springencompassing said shaft and having its inner end anchored to the innerend of the shaft, a sleeve mounted on said spring, said spring havingits outer end anchored to said sleeve, an annulus revolubly mounted onsaid element being formed with a pair of oppositely disposed cutoutportions opening at its inner edge, a coupling member encompassing andxed to the annulus and revoluble about said element being formed withinwardly extending arms provided with couplers, a cap fixedly securedwith said cylinder and member, encompassing the latter and concealingthe outer face of said annulus, a pair of oppositely disposed dogsarranged in said cutouts and being formed with noses for engagement insaid element to arrest the revolving of the cylinder, said dogs havingparts co-acting with the edge portions of said cutouts to provide forthe dogs fulcruming within the annulus, and an outer transmitting springbinding said sleeve and having its inner end anchored to the body of thesleeve, said outer spring having its outer end extending through saidcouplers whereby said outer spring is connected with the cylinder.

6. In a power unit, a bodily revoluble structure, a stationary supportfor the structure, a power transmiting spring for revolving saidstructure and having one end anchored to said support, said structurerevolubly mounted on said support and formed of a cap member includingan axially apertured disc provided at its outer edge with a rearwardlyextending annular flange of angle-shape cross section, an annuluspositioned against the inner face of the disc formed with a pair ofoppositely disposed cutout openings at the inner edge thereof, saidflange being disposed in overlapping relation with respect to the outeredge of the annulus, a coupling member having a part interposed betweensaid flange and annulus, said member abutting the rear face of theannulus and including rearwardly extending arms formed with couplers forconnecting thereto the other end of said spring a pair of oppositelydisposed latching dogs mounted in said cutouts for engaging into saidsupport to latch the said structure from movement, said dogs and thewalls of the cutouts having coacting means to provide for the dogsfulcruming on parts of said walls, and said part, ange and outer edge ofthe annulus having coacting means for connecting them together.

7. In a power unit, a power transmitting means for operating a revolubleelement, said means including a revoluble coupling member, inner andouter concentrically arranged power springs, a sleeve interposed betweensaid springs, a revoluble latching member for said coupling element, arevoluble cap member fixed to and for revolving said element, astationary supporting structure common to said members, sleeve andsprings and upon which said members revolve, said inner spring havingone end connected to said structure and its other end to said sleeve,said outer spring having one end connected to said sleeve and its otherconnected to said coupling member, said outer spring having coil thereofextending through the body of said sleeve, said latching member andstructure having coacting parts for latching said coupling member, thesaid members having coacting interengaging parts to provide for thebodily revolving thereof in unison.

O'I'IO A. FRITZ.

